In the production of frozen comestibles, such as ice cream, a liquid composition comprising a fat component, a sugar component, a water component, and other flavouring agents are mixed together. The temperature of the composition is generally then reduced to about −5° C. to −8° C. while the mixing continues. Once temperature of the composition has been reduced, it is transferred into vessels for shaping and further freezing until the composition substantially solidifies.
As used herein, the ‘comestible’ makes reference to an article of food, which may be consumed.
In order to obtain the correct consistency, the degree of freezing required is dependent on the ratio of sugar, fat and other ingredients in the composition. The liquid composition, therefore, is imparted with a “freeze point depression” as a result of the various ingredients affecting the freezing point of the composition. The imparted freeze point depression can be characterized in terms of the sucrose equivalency of the liquid composition. The sucrose equivalency of a given liquid composition includes the contribution of the components of the composition, such as milk solids or glucose components and other ingredients included in the liquid composition. The sucrose equivalency is a measurement known in the industry and is used to compare the freezing requirements of a given liquid composition to the freezing rates and temperature of various concentrations of sucrose in water so as to provide a standard against which to measure the freeze point depression. For example, for a given ingredient in aqueous solution, the equivalent concentration of sucrose that would have the same freezing point depression effect can be calculated. Thus, the sucrose equivalency allows the freezing point depression effect caused by a particular ingredient in the composition to be calculated.
Therefore, when producing many frozen comestibles, the sucrose equivalency of the ingredients is calculated so as to determine the freezing point depression to determine the freezing conditions required to obtain a substantially uniform consistency of the resultant frozen comestible. For example, the ratios of the various ingredients can be adjusted such that the amount of each ingredient results in a substantially consistent freezing point for all the ingredients. However, if an ingredient is present in the liquid composition that has a much higher sucrose equivalency or significantly lower freezing point than the other ingredients, adjustment of the ingredient ratios may not be possible to obtain the desired frozen comestible. The result is that the frozen comestible lacks a smooth consistency since the water component, or other possibly other components, freezes well before the other ingredients.
Furthermore, some ingredients, such as alcohol have a non-linear sucrose equivalency with increasing concentrations in a given fluid medium. Alcohol (ethanol), for example, has a geometrically progressive effect on freezing point depression. For example, a 2.5% concentration equates to a sucrose equivalency of 17, and a 17.5% concentration equates to a sucrose equivalency of 126. The result of freezing liquid compositions which contain alcohol, under conditions hereinabove described, is undesirable as ice crystal agglomerations or ice crystal striations or “pockets” of ice crystals are formed in the frozen comestible and therefore not having a smooth consistency.
Also, with some desirable ingredients, the ratios cannot be adjusted so as to obtain the desired uniform consistency of the frozen comestible while maintaining the desired flavor and other properties of the frozen comestible. As noted above, such pockets of ice crystals are found when freezing liquid compositions that include an alcohol component using the hereinabove described techniques for making a non-alcohol-containing frozen comestible. Therefore, it would desirable to develop a process for freezing compositions that include an alcohol component in which the resulting frozen composition is substantially devoid of ice crystal striations or pockets and has an ice cream-like consistency at a serving temperature. Furthermore, it would be desirable to provide a process for producing a stable frozen alcohol-containing comestible which can be stored and served at product temperatures normally associated with conventional ice creams.